1. Technical Field
The disclosure generally relates to a touch panel, and more particularly, to a multi-touch detection method for a touch panel.
2. Description of Related Art
Types of conventional touch panels mainly comprise resistive touch panels, capacitive touch panels, infrared rays touch panels, and surface acoustic wave touch panels. Generally, resistive touch panels, such as four lines type or five lines type touch panels, can only detect a single touch action at the same time in use because voltage variations of conductive films are detected by using an analogical method. When users touch resistive touch panels in a multi-touch action, an erroneous operation may be generated.
US patent applications No. US2006/0097991 and US2008/0158181 disclose structures of capacitive touch panels capable of performing multi-touch detection, which generally include two transparent conductive layers respectively disposed on opposite side surfaces of transparent glass substrates. According to the product resolution, two transparent conductive layers need to be respectively processed through a photolithography process. Conducting wires formed on the same transparent conductive layer are disposed apart and in parallel to each other. The conducting wires formed on one of the transparent conductive layers are perpendicular to that formed on another transparent conductive layer. During operation, by repeating to scan each of the conducting wires, variations of capacitances thereof are analyzed to determine the coordinates of contact points of users' fingers.
However, the difficult photolithography processes are necessary for forming the foregoing capacitive touch panels. The product yield may be low due to the difficult photolithography processes. The driving method is complex for recognizing the contact point on touch panel. Accordingly, although capacitive touch panels can be applied for detecting multi-touch action, the high cost limits the scope of the application.